Spinning frame having bowl spindles

ABSTRACT

In a spinning frame having open end spinning spindles, the spinning process is to be prevented from becoming unprimed, if the frame stops, by a notched rod which may slide and turn in front of the outlets of the spindles. A tachometric device causes the rod to slide into a position for forming reserve loops in the threads, and ensures stoppage of the feed to the spindles and of the withdrawal of the threads when, through inertia, the spindles, ceasing to be driven, pass through a pre-determined spinning speed. On restarting, when passing through the same speed, the rod turns and the notches free the previously-formed reserve loops of thread.

1451 Sept. 25, 1973 SPINNING FRAME HAVING BOWL I SPINDLES I Inventors: Jacques Le Chatelier, Riedisheim;

Regis LaFlaquiere, Mulhouse, both of France Assignee: Societe Alsacienne de Constructions Mecaniques de Mulhouse societe francaise, Mulhouse, France Filed: June 17, 1971 Appl. No.: 153,933

Foreign Application Priority Data June 17, 1970 .France 7022248 References Cited UNITED STATES PATENTS 8/1967 Mikulecky et a1. 57/58.89 X

3,541,774 11/1970 Sterba et al 57/5895 X FOREIGN PATENTS OR APPLICATIONS l,550,l89 11/1968 France 57/58.89

Primary ExaminerDonald E. Watkins Attorney-Holman & Stern [5 7 ABSTRACT In a spinning frame having open end spinning spindles, the spinning process is to be prevented from becoming unprimed, if the frame stops, by a notched rod which may slide and turn in front of the outlets of the spindles. A tachometric device causes the rod to slide into a position for forming reserve loops in the threads, and ensures stoppage of the feed to the spindles and of the withdrawal of the threads when, through inertia, the spindles, ceasing to be driven, pass through a predetermined spinning speed. On restarting, when passing through the same speed, the rod turns and the notches free the previously-formed reserve loops of thread.

' 13 Claims, 12 Drawing Figures PAILNTH] SH? 5 I915 SHEET 1. OF 6 PATENTED SEPZ 5 I973 SHEET 2 [IF 6 2&0 on

la-aao PATENTED SEPZSIBYS SHEET 3 BF 6 PATENTED SEPZ 5 I973 SHEET 5 OF 6 1 SPINNING FRAME HAVING BOWL SPINDLES BACKGROUND OF THE INVENTION This invention relates to a spinning frame having open end spinning spindles arranged in alignment and adapted to be rotated by a main motor, means for feeding fibers to the open end spinning spindles and withdrawing means for withdrawing the spunthread at the spindle outlets.

More particularly, the invention relates to a device in such a spinning frame for permitting avoidance of depriming of the spinning process when the spindles stop, either accidentally, or as a result of a voluntary stopping maneuver, so that the thread formation resumes normally when the process is restarted, and so that the newly-formed thread is connected to the preceding thread without forming a piece of thread of mediocre quality.

In order to obtain this result, the invention is based on a process which comprises producing, immediately before a spindle stops, a reserve of thread at the outlet of the latter, and freeing said reserve of thread when the spindle is restarted.

Devices already exist for putting this process into effect.

PRIOR ART Another device, disclosed in French Pat. No.

l,543,8 l 5, comprises at the outlet of the open end spinning spindle a sliding thread-guiding rod which causes the thread to deviate laterally by a predetermined amount, in order to make it form a reserve loop. Devices of this type have relatively large inertia when the reserve of thread is freed, by virtue of the intrinsic inertia of the thread-guiding rod, and of the elements controlling it. In addition, the open end spinning spindle stops at the end of a period of time which is not precisely determinable, for it is a function of mechanical frictions which are themselves variable in time for a determined machine.

OBJECT AND SUMMARY OF THE INVENTION An object of the present invention is to provide a device for the purpose aforesaid, which does not have the above-mentioned drawbacks.

According to the present invention, the threadguiding rod is parallel to the direction of alignment of the open end spinning spindles, has thread-guiding notches, and is so mounted as to be able also to pivot under the action of rotation-controlling means, the frame comprising a tachometric device, on the one hand, for setting in operation the means for controlling movement of the rod to its reserve position and for ensuring stoppage of the means for feeding the open end spinning spindles with fibers, and of withdrawal means for the thread at the outlets of the open end spinning spindles when, after the main motor stops, the decreasing rotary speed of the spindles passes a predetermined spinning speed and, on the other hand, for ensuring restarting of the means for feeding the spindles with fibers and of the thread withdrawal means, and for actuating the rotation-control means, so that the threadguiding notches suddenly free the threads when, after the main motor is restarted, the increasingrotary speed of the open end spinning spindles passes the abovementioned predetermined spinning speed, and then for actuating the translation-control means in order to return the rod to its operative position.

Such a device has a number of advantages, as follows.

In effect, a single thread-guiding rod is sufficient to control the re-priming of a whole series of open end spinning spindles. The rod may be very light and therefore of low inertia. Given that the freeing of the reserve loops of threads is produced by a rotary movement which forces the notches to free the threads, the threads, whose inertia is practically negligible, may thus resume almost instantaneously their initial path without the need for concern about bringing the rod back into its initial operating position in a very short time. As the procedure for forming the reserve of thread, and its re-absorption, is ensured by a tachometric system in response to the spinning speed of the turbines, i.e. under very precise operating conditions of said turbines, the most favorable conditions for repriming are thus satisfied. In effect, one need not concern oneself about possible variations in the deceleration or acceleration curves of the open end spinning spindles, which may be influenced by very appreciable variations in friction in the various rotating elements. The reserve of thread is formed without taking account of the tension of the thread between the outlet of the spindles and the withdrawal cylinders.

Given that the thread, between the outlet of the open end spinning spindles and the withdrawal rollers, presents a certain degree of torsion, it exerts a torque on its ends. The end located between the withdrawal rollers is naturally held, but its other end is no longer entrained by the spindle when the latter stops, and it might have a tendency to turn.

In order to avoid this drawback, the translationcontrolling means for the thread-guiding rod may be designed and constructed so that, on the one hand, the rod, on stoppage of the frame, after reaching its reserve-forming position, retracts a short distance, in order to allow the reserve loops of thread to form a twist for absorbing the torsion of said thread loops, and, on the other hand, in order that, at the moment when the open end spinning spindles start, said rod begins by travelling the short distance, to reach its extreme reserve position, thus ensuring re-absorption of the twists of thread.

Thus, when the spindles stop, a reserve of thread is formed and, immediately afterwards, this reserve is relaxed by the slight retraction of the thread-guiding rod so that, on each piece of thread between a spindle and the corresponding withdrawal rollers, a twist forms which reduces the torque exerted on the free end of the thread. When the spindle is restarted, the threadguiding rod temporarily resumes its extreme reserveforming position, and consequently tensions the thread, re-absorbing the twist; the torsion which was in the thread before formation of the twist is now integrally restored to it. This helps to avoid any discontinuity in the quality of the thread when the frame stops.

The thread-guiding rod, during the entire period of normal operation of the open end spinning spindles, may be subjected to the action of means adapted to impose on it a longitudinal, short-amplitude reciprocating movement, in order to avoid any localised wear on the withdrawal rollers.

An embodiment will now be described, by way of example, with reference to the accompanying drawings, in which:

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagrammatic perspective view of part of a spinning frame equipped with a device according to the present invention for avoiding de-priming of the open end spinning spindles when they stop;

F IG. 2 is a sectional view on a larger scale along the line lI-II of FIG. 3, showing the rotation-control device of the thread-reserve formation rod to the righthand side of FIG. 1;

FIG. 3 is a sectional view along the line III-III of FIG. 2;

FIG. 4v is a sectional view substantially along the line IV-IV of FIG. 5, showing the displacement control device of the thread-reserve forming rod shown to the left-hand side of FIG. 1; v

FIG. 5 is a section substantially along the line V-V of FIG. 6;

FIG. 6 is a plan view corresponding to FIG. 5;

FIG. 7 is a part-sectional elevation on a larger scale, showing thread withdrawal rollers, and the thread reserve-forming rod, in the normal operative position;

FIG. 8 is a section along the line VIIIVIII of FIG.

FIGS. 8A and 8B are detail views of FIG. 8 on a larger scale, in two different positions respectively;

FIG. 9 is a view similar to FIG. 7, at the moment of formation of the thread reserve, and

FIG. 10 is a graph showing the speeds of the open end spinning spindles as a function of the operating sequences of the device for avoiding de-priming of the spindles.

DETAILED DESCRIPTION OF THE DRAWINGS A spinning frame shown partially and diagrammatically in FIG. 1 comprises a series of open end spinning spindles 11 supported by a frame indicated generally by 12. The spindles 1 l are rotated, preferably individually, e.g. by a belt transmission 13 as shown, and as described and illustrated in Ser. No. 58,931 now U. S. Pat. No. 3,668,854 of June 13, 1972.

Each of the belt transmissions 13 comprises a pulley 16 having a shaft driven by a tangentially-engaging belt 17 through pulleys I8 and 19. The pulley 19 is mounted on a vertical shaft 23 of a main electric motor 24, and the pulley 18 is supported by a vertical shaft 26 which, through a transmission comprising a worm 27, a worm wheel 28, a horizontal shaft 29, an electromagnetic clutch 32, a train of gearwheels 33,34,35 and a shaft 36 and, drive rollers 37 which feed the spindles 11 with textile fibers 39.

Spun threads 42 emerging from the spindles 11 are withdrawn by rollers 43,44. The latter are fixed on a horizontal shaft 46 driven by the gearwheel 35 via gearwheels 51,52,53 and 54.

Each spindle 11 is connected to a suction main 61 by a tube 62, and the main 61 is connected by a tube 63 to a suction fan 64 driven by an electric motor 65.

In order to avoid de-priming of the turbines, when they are voluntarily stopped, or in the case of a power breakdown, a device is provided comprising a horizontal rod 71, which may be circular in cross-section, or partially circular (see FIGS. 7 and 8), and may have notches 72 with flat bases formed, if necessary, by added pieces, in the normal path of each thread 42, be tween the outlet of the spindle 11 and nip of the withdrawal rollers 43,44.

The rod 71 serves to form a reserve of thread when each spindle 11 stops, and, for this purpose, is so mounted as to enable it to slide axially and to pivot around its axis; and in the vicinity of one end of the rod 71 there is fixed an apertured guide member 75 (see also FIGS. 4 and 5) which has cheeks 76,77. The member 75 can turn and slide in a guideway 78 in a slide 79 mounted in a cylinder 81 which is fixed to part of the frame 12. For clarity of illustration, these parts have been shown very schematically in FIG. 1, and slightly differently from their real form, which is shown in detail in FIGS. 4 and 5.

The cheeks 76,77 of the member 75 hold a bearing 83 made up, for example, of a ball bearing mounted on a crank pin 84 on an output shaft 85 of a reductiongear electric motor 86 carried on a support 87 integral with the slide 79.

The slide 79 can be moved in the cylinder 81 by means of double-acting pneumatic ram 91, via a transmission comprising a vertical toothed rack 94 integral with a piston rod 93 of the ram 91, a pinion wheel 95 meshing with the rack 94 and carried by a horizontal shaft 96, a pinion wheel 97 also carried by the shaft 96, and a horizontal rack 98 integral with the slide 79.

At the end of its down stroke, the lower end of the vertical rack 94 compresses a spring 101 which is supported against a base 102 (FIG. 5) ofa vertical cylinder 103 which guides the rack 94. The top end of spring 101 is retained by a ring 105 integral with a rod 106 which passes through the base 102 of the cylinder 103 and serves to actuate a stroke-limit switch 107 (FIG. 1).

Thus, by means of the ram 91, the slide 79 may be moved horizontally by the rack 98 and the pinion 97, and, consequently the rod 71 may be moved by a distance indicated by d in FIG. 1, and which is, e.g., of the order of mm. Slow rotation of the output shaft 85 of the motor 86 has the purpose, during normal operation, of ensuring an oscillating low-amplitude movement d1 (FIG. 7) to said rod, so as to prevent the thread 42 drawn by the rollers 43,44 from bearing on the rollers 43,44 always at the same point.

Pivotal movement of the rod 71 is effected by a pneumatic ram 111, through an intermediate transmission comprising a vertical rack 114 integral with a piston rod 113 of the ram 111 (see also FIG. 2), and a pinion wheel 115 having a square-section socket in which there may slide a rod 116, which is of corresponding cross-section, and is made integral with the rod 71 by a coupling sleeve 109 (FIG. 3). The body of the rack 114 (FIG. 2) is of a generally cylindrical shape and can slide in a chamber 117 of a vertical cylinder 18 carried by a support 119 fixed to the frame 12 (see also FIG. 3). The pinion wheel 115 is rotatably supported at both ends by bearings 121,122 mounted in a the support 119.

On the top end of the rack 114, there is mounted an axial pin 124 for actuating a trip 125 which controls a stroke-limiting micro-switch 126. The pin 124 is screwed into the rack 114 so that it may be accurately adjusted by screwing it more or less deeply into the rack.

The ram 91 (FIG. 1) is supplied from a compressedair distribution pipe 141 through a reversing electrovalve EV3 and another electro-valve EV2 connected as shown in FIG.. 1. The top and bottom connections of the cylinder 92 of the ram 91 are indicated by 142 and 143 respectively.

The ram 111, controlling rotation of the rod 71, is supplied from a compressed-air pipe 145, through a reversing electro-valve EV1. The top and bottom connections of the cylinder 112 of the ram 111 are indicated by 146 and 147 respectively.

The electrical layout shown in FIG. 1 also has a main starting switch M and a stop button A. A tachometric relay 151 controlled by a tachometric dynamo 152 whose rotor is integral with the rotor of the main motor 24, comprises a closure contact which closes when, during run-up, the open end spinning spindles 11 reach a predetermined speed, e.g. of the order of 15,000 r.p.m., said contact being closed from this moment, while the speed of the spindles 11 continues to increase and reaches the nominal speed, e.g. about 35,000 r.p.m. This contact remains closed during the whole period of normal operation of the turbines, but opens again when their decreasing speed passes through the above predetermined value of about 15,000 r.p.m.

The lay-out also comprises a manocontact M1 incorporated in the suction pipe 63 of the. fan 64.

The spinning frame operates as follows.

There will be described, one by one, the operational sequences numbered to 6 (FIG. 10), for starting and setting in operation, then sequences numbered 7 to 9 for a normal stoppage, and sequences 7, 8', 9' for a stoppage due to an electric current breakdown.

Sequence 0: The electrical installation is not supplied with voltage, but the pneumatic installation is connected to the compressed-air pipes 141 and 145. The top connection 142 of the ram 91 controlling movement of the rod 71 is linked to the atmosphere via the electro-valves EV2 and EV3. The bottom connection 145 of the ram 91 is connected to the atmosphere by the electro-valve EV3. The piston 93 of the ram 91 is in the down position and the bottom end of rack 94 rests on the decompressed spring 101, so that the slide 79 and the rod 71 are moved to the left relative to the position shown in FIG. 1, through the distance d (or l lmm. in the example), decreased by a small distance of about l0mm., corresponding to the height occupied by spring 101 when the piston of the jack 91 is pushed down at the end of the stroke, under the effect of compressed air, during an operational phase which will be seen later. I i

Each thread 42 emerging from a spindle 11 and ensocket 123 in gaged in a notch 72 (FIG. 8A) of the thread-guiding rod 71, is thus deflected to the left as shown in full lines in FIG. 9.

The top connection 146 of the ram 111 controlling rotation of rod 71 is connected to the compressed-air pipe 145 by the electro-valve EV1 when at rest, while its bottom connection 147 is connected to the atmosphere by the same electro-valve. The piston 113 of the The actuation of the relay X permits power to be supplied to a contactor C1 which is neutralised by the stroke-limit switch 107.

Sequence 2: The manostat M1, connected to the pipe 63 of the suction fan 64, closs its electrical contact, thus supplying electrical power to the electro-valve EV2 and, in consequence, admitting compressed air to the top connection 142 of the ram 91 through thenonexcited electro-valve EV3. The piston 93 of the jack 91 descends by 10mm, compressing the spring 101, so that the slide 79 moves the rod 71 slightly further to the left, by an amount d2 (FIG. 9). Each thread 42, still engaged in a notch of the rod 71, is untwisted, for reasons which will be understood later.

Sequence 3: Given that the compressedair has just been admitted to the top connection 142 of the ram 91, the piston of the latter descends, closing the strokelimit switch 107 and cutting off the power to the supply contactor C1. By means of the belts l7 and 13, the spindles 11 start, and progressively accelerate. However, the electro-magnetic clutch 32 is not yet excited, so that the supply roller 37 and the withdrawal rollers 43,44 are not yet in rotation.

Sequence 4: The open end spinning spindles l1 reach the abovementioned predetermined speed, of 15,000 r.p.m. in the example. At this instant, the voltage supplied by the tachometric dynamo 152 closes the contact of the relay 151; the electromagnetic clutch 32 is excited via the relay R2, so that the rollers 37 and the rollers 43,44 begin to move; at the same time the coil of EV1 is supplied with current through the contacts or relays R4, Y and R2, so that the bottom connection 147 of the ram 111 is connected to the compressed-air pipe 145, while its top connection 146 is connected to the atmosphere.

Sequence 5: The piston of the ram 111 rises with the rack 114 which turns the pinion wheel 115 and with it the rod 71. The notches 72 move away and free the threads 42, while the previously-formed reserve of thread is re-absorbed, the thread passing from the position in FIG. 9 to that in FIG. 7. Also, the piston of the ram only carries out a transitory rising movement because, as soon as the pin 124 actuates the stroke-limit switch 126, the latter supplies current to the relay Y, the power of the electro-valve EV1 is cut off, and the top connection 146 of the ram 111 is reconnected with the compressed-air pipe 145, while the bottom connection 147 is connected to the atmosphere, thus causing the piston of the'ram, and the rack 114 to descend, so that the notches 72 of the rod 71 resume their normal position (FIGS. 8 and 8A) in the path of threads 42.

The supply of power to the relay Y also ensures power supply to a relay R4 which excites the electrovalve EV3 and consequently the ascent of the piston of the ram 91. The rack 94, rising again fully, shifts the slide 79 and the rod 71 fully to the right into the normal operative position as shown in FIGS. 1 and 7.

The power supply to the relay R4 also excites a contactor C5 for supplying the motor controlling the oscillation of the rod 71 over the stroke d1 (FIG. 7). If the threads 42 are not already in corresponding notches 72, they fall easily into them at this point.

At the end of this sequence, the operating conditions of the machine are almost those of normal operation, except that the r.p.m. of the spindles 11 is less than the nominal speed, e.g. 20,000 r.p.m. Their speed continues to rise progressively.

Sequence 6: The open end spinning spindles reach their nominal speed, of the order of 35,000 rpm. in the example. The rams 91 and 111 remain in the last condition in which they were placed, the electric motor drives the spindles 11 and the roller 37.and 43,44, because the electromagentic clutch continues to be excited by the tachometric contact 151 which has remained closed since the spindles 1 1 reached the abovementioned predetermined speed, of the order of 15,000 r.p.m. in the example, i.e. since sequence 4. For the same reason, the motor 86 continues'to produce the small longitudinal oscillation of the rod 71. All the threads 42 are in the corresponding notches 72 of the rod (FIG. 7).

Sequence 7: It is desired to stop the frame. The stop button A is pressed, the relay X receives no further power, causing the contactor C1 feeding the main motor 24 to close, the motor 24 and the elements it drives continuing to turn through inertia, and gradually slowing. Cutting off the relay X also cuts-off of power to the contactor C4 controlling the motor 65 for the fan, with this power supply being continued for the moment by the relay R2.

Sequence 8: The rotary speed of the spindles 11 progressively drops, and passes through the abovemen tioned predetermined value, of the order of 15,000 r.p.m. The tachometric contact 151 opens, the relay R 2 receives no further power, the electromagnetic clutch 32 is no longer excited, the rollers 37 and 43,44stop turning, cut-off of the relay R2 causes the relay R4 to be cut off also, the electrovalve EV3 is no longer excited, so that the piston of the ram 91, and the rack 94, descent under the action of compressed air admitted to the top connection 142 of the ram 91, and cause the slide 79 and the rod 71 to move to the left by the distance d because, under the pressure of the compressed air the spring 101 is compressed.

All the threads 42 still engaged in the notches of the rod 71 are deflected to the left by,l lmm., as shown in broken lines in FIG. 9. Thus, a reserve of threads is formed, made up of those parts of the threads which are deflected laterally between the outlet of the spindles l1 and the withdrawal cylinders.

The cut-off of the relay R2 also causes the contactor C4 to be cut off, so that the suction fan drive motor 65 receives no further power.

Thecut-off of the relay R4 causes the contactor C5 to be cut off and, consequently, the mOtor 86 controlling the oscillatory movement.

Sequence 9: Stoppage of the suction fan 64 causes the contact of the manostat M1 to open and consequently removes excitation from the electrovalve EV2. The top connection 142 of the ram 91 is connected to the atmosphere by the electrovalve EV2, and the spring 101 expands, causing the rack 94 and the piston of the ram 91 to rise by 10mm. The slide 79 and the rod 71 thus move 10mm. to the right, so that the threads now occupy the position shown in full lines in FIG. 9. The 10mm. reverse of the rod 71 is very important. In fact, given that the part of each thread 42 between the bowl open end spinning spindle outlet and the rollers 43,44 has a certain degree of torsion, it exerts a torque on both its ends. Now, the bottom end of this part of the thread is held in the nip between the rollers 43,44, so that the top end, which is no longer driven by the spindle 11, would tend to turn in a false twist device arranged at the open end spinning spindle outlet. The reverse movement of the rod 71 causes a decrease in the tension on that part of the thread, so that the latter forms a twist capable of absorbing the torsion and, consequently, of sufficiently reducing the torque exerted on the top free end of this part of the thread.

It has been seen above, in the description of Sequence 2, that, on starting the rod 71 undergoes a small transitory shift of 10mm. to the left, so that the twist in question is re-absorbed and the thread resumes its normal tension.

At the end of this sequence 9, the piston of the ram 91 takes its Support on the spring 101 via the toothed rack 94.

All the elements have returned to their respective positions as in sequence 0.

If there is a power breakdown, the necessary auxiliary and control relays are still supplied from an emergency source; instead of being stopped by the frame, the drive motor 65 0f the Suction fan 64 stops slightly sooner, i.e. in Sequence 7 which corresponds to Sequence 7, instead of in Sequence 8' which corresponds to Sequence 8, but the inertia of the fan rotors and of the motor is sufficient to maintain suitable low pressure in the spindle 11 until Sequence 9 which corresponds to Sequence 9.

The cross-hatched zone in the graph in FIG. 10 shows the zone of uncertainty of natural stoppage of the turbines.

The machine is not affected by this uncertainty, for all precautions for avoiding de-priming or the necessity to re-prime the open end spinning spindles have been taken, under the control of the tachometric relay, when the deceleration speed of the bowl spindles 11 passes through said predetermined speed, i.e. about 15,000 rpm. in the example considered.

Naturally, the invention is not limited to the embodiment described and illustrated, which has been given by way of example; and modificataOns may be made to it, dependent upon the applications envisaged, without however going beyond the scope of the invention defined in the appended claims.

We claim:

1. A device for avoiding de-priming upon stoppage of open end spinning spindles having outlets, said spindles being aligned on a frame and rotated by a main motor, in which said frame includes means for feeding the open end spinning spindles with fibers, and withdrawal means for the thread at the spindle outlets, said device comprising, in front of the outlets of the spindles a thread-guiding rod slidable in a direction perpendicular to the axes of the spindle, between an operational position in which each thread-guiding rod is in the normal path of the thread emerging from its corresponding open end spinning spindle, and a reserve position at a predetermined distance from said operative position, movement-control means operably related to the thread-guiding rods for effecting the sliding of the rods, the thread-guiding rod, being parallel to the direction of alignment of the bowl spindles, having threadguiding notches, rotation control means, means mounting the rod to pivot under the action of the rotationcontrol means, the frame also comprising a tachometric device for actuating the translation-control means for placing the rod in the reserve position and ensuring stoppage of the means for feeding fibers to the open end spinning'spindles and of the thread withdrawal means when, after stoppage of the main motor, the decreasing rotary speed of the spindles passes through a predetermined spinning speed and, for ensuring restarting the means for feeding fibers to the spindles, and the thread withdrawal means, and for actuating the rotation-control means so that the thread-guiding notches suddenly free the threads when, after restarting the main motor, the increasing rotary speed of the spindles passes through the above mentioned predetermined speed, and then for actuating the translation-control means for returning the rod to the operative position.

2. The device as claimed in claim 1, in which the translation-control means for the thread-guiding rod is so designed and constructed that, on the one hand, said rod, on stoppage of the frame, after reaching its reserve position, retracts a short distance to allow the reserve loops to form a twist, absorbing the torsion of the loops of thread, before starting the spindles, and said rod starts by covering the above short distance, to reach its extreme reserve position and ensure reabsorption of the twists of thread.

3. The device as claimed in claim 1, in which the translation-control means of the thread-guiding rod comprises a fluid pressure ram having a piston and a spring influencing the piston at one end of its stroke.

4. The device as claimed in claim 1 including a tachometric device, a clutch controlled by the tachometric device, and the means for feeding fibers to the bowl spindles, and the thread withdrawal mens being driven by the main motor through theclutch controlled by the tachometric device.

5. The device as claimed in claim 1, in which the rotation-control means for the thread-guiding rod is so designed and constructed that said rod resumes its initial angular operative position immediately after turning to the position in which the notches free the threads which have been deflected from their normal path.

6. The device as clalmed in claim 1 including a suction fan connected to the spindles, a manocontact sensitive to low pressure generated by the fan, a contactor controlled by the manoc'ontact for supplying power to the main motor, a drive motor on theframe for the fan, a circuit for'supplying power for the fan drive motor, and a stroke-limit switch actuated in response to the thread-guiding rod adopting its reserve-formation position controlling the circuit.

7. The device as claimed in claim 1 including longitudinal low-amplitude oscillating movement imparting means subjecting the thread-guiding rod, during the entire period of normal operation of the open end spinning spindles, to longitudinal low-amplitude oscillating movement.

8. The device as claimed in claim 7, including a slide connected to said translation-control means, the thread-guiding rod being supported by the slide and connected axially to said slide by the said longitudinal low-amplitude oscillating movement imparting means.

9. in a spinning frame having at least one open end spinning spindle, a device for avoiding de-priming upon stoppage of an open end spinning spindle, said device including a thread-guiding rod arranged substantially on the normal path of the thread emerging from the open end of the spinning spindle, support means supporting the thread-guiding rod for translational sliding and pivotal movements of the thread-guiding rod, at least one thread-guiding element on the threadguidinG rod, translational sliding movement control means for moving the thread-guiding rod between an operative position in which the thread-guiding element is in the normal path of a thread emerging from the open end spinning spindle and a reserve position at a predetermined distance from the operative position, the threadguiding rod being adapted to assume either an operative angular position in which the thread-guiding element can engage the thread and an a release angular position in which the thread-guiding element cannot retain the thread and pivotal movement control means for pivoting the thread-guiding rod out of the operative angular position with in the reserve position to allow the thread to abruptly freely disengage the threadguiding element and to skid along the thread-guiding rod to its normal path.

10. The device claimed in claim 9, for a frame with a plurality of open end spinning spindles, in which a plurality of thread-guiding elements are provided, and each of the thread-guiding elements being defined by a transverse notch in the thread-guiding rods.

11. The device as claimed in claim 10, in which the thread guiding rod is mounted for sliding movement in a direction at right angles to the axis of the open end spinnind spindle.

12. The device as claimed in claim 9 for a frame with a plurality of aligned open end spinning spindles, wherein the direction in which the thread-guiding rod is adapted to slide is parallel to the direction in which the open end spinning spindles are aligned.

13. The device as claimed in claim 9 further including a motor for rotating theopen end spinning spindle, feeding means for feeding the open end spinning spindles with textile fibers, thread withdrawal means, and a tachometer device to actuate the translational sliding movement control means for placing the threadguiding rod in the longitudinal reserve psoition and insuring stoppage of the feeding means and the withdrawal means, when, after stoppage of the open end spinning spindle driving motor, the decreasing rotary speed of the open end spinning spindle passes through a predetermined threshold spinning speed, and also for restarting the feeding means and the withdrawal means together with the thread-guiding rod pivoting means to temporarily position the thread-guiding element in thread-releasing position when the increasing rotational speed of the open end spinning spindle passes through the pre-determined threshold spinning speed, then to activate the translational sliding movement control means to reset the thread-guiding rod into the operative position. 

1. A device for avoiding de-priming upon stoppage of open end spinning spindles having outlets, said spindles being aligned on a frame and rotated by a main motor, in which said frame includes means for feeding the open end spinning spindles with fibers, and withdrawal means for the thread at the spindle outlets, said device comprising, in front of the outlets of the spindles a thread-guiding rod slidable in a direction perpendicular to the axes of the spindle, between an operational position in which each thread-guiding rod is in the normal path of the thread emerging from its corresponding open end spinning spindle, and a reserve position at a predetermined distance from said operative position, movement-control means opeRably related to the threadguiding rods for effecting the sliding of the rods, the threadguiding rod, being parallel to the direction of alignment of the bowl spindles, having thread-guiding notches, rotation control means, means mounting the rod to pivot under the action of the rotation-control means, the frame also comprising a tachometric device for actuating the translation-control means for placing the rod in the reserve position and ensuring stoppage of the means for feeding fibers to the open end spinning spindles and of the thread withdrawal means when, after stoppage of the main motor, the decreasing rotary speed of the spindles passes through a predetermined spinning speed and, for ensuring re-starting the means for feeding fibers to the spindles, and the thread withdrawal means, and for actuating the rotation-control means so that the thread-guiding notches suddenly free the threads when, after re-starting the main motor, the increasing rotary speed of the spindles passes through the above mentioned predetermined speed, and then for actuating the translation-control means for returning the rod to the operative position.
 2. The device as claimed in claim 1, in which the translation-control means for the thread-guiding rod is so designed and constructed that, on the one hand, said rod, on stoppage of the frame, after reaching its reserve position, retracts a short distance to allow the reserve loops to form a twist, absorbing the torsion of the loops of thread, before starting the spindles, and said rod starts by covering the above short distance, to reach its extreme reserve position and ensure reabsorption of the twists of thread.
 3. The device as claimed in claim 1, in which the translation-control means of the thread-guiding rod comprises a fluid pressure ram having a piston and a spring influencing the piston at one end of its stroke.
 4. The device as claimed in claim 1 including a tachometric device, a clutch controlled by the tachometric device, and the means for feeding fibers to the bowl spindles, and the thread withdrawal mens being driven by the main motor through the clutch controlled by the tachometric device.
 5. The device as claimed in claim 1, in which the rotation-control means for the thread-guiding rod is so designed and constructed that said rod resumes its initial angular operatIve position immediately after turning to the position in which the notches free the threads which have been deflected from their normal path.
 6. The device as claImed in claim 1 including a suction fan connected to the spindles, a manocontact sensitive to low pressure generated by the fan, a contactor controlled by the manocontact for supplying power to the main motor, a drive motor on the frame for the fan, a circuit for supplying power for the fan drive motor, and a stroke-limit switch actuated in response to the thread-guiding rod adopting its reserve-formation position controlling the circuit.
 7. The device as claimed in claim 1 including longitudinal low-amplitude oscillating movement imparting means subjecting the thread-guiding rod, during the entire period of normal operation of the open end spinning spindles, to longitudinal low-amplitude oscillating movement.
 8. The device as claimed in claim 7, including a slide connected to said translation-control means, the thread-guiding rod being supported by the slide and connected axially to said slide by the said longitudinal low-amplitude oscillating movement imparting means.
 9. In a spinning frame having at least one open end spinning spindle, a device for avoiding de-priming upon stoppage of an open end spinning spindle, said device including a thread-guiding rod arranged substantially on the normal path of the thread emerging from the open end of the spinning spindle, support means supporting the thread-guiding rod for translational sliding and pivotal movements of the thread-guiding rod, at least one thread-guiding element on the thread-guidinG rod, translational sliding moveMent control means for moving the thread-guiding rod between an operative position in which the thread-guiding element is in the normal path of a thread emerging from the open end spinning spindle and a reserve position at a predetermined distance from the operative position, the thread-guiding rod being adapted to assume either an operative angular position in which the thread-guiding element can engage the thread and an a release angular position in which the thread-guiding element cannot retain the thread and pivotal movement control means for pivoting the thread-guiding rod out of the operative angular position with in the reserve position to allow the thread to abruptly freely disengage the thread-guiding element and to skid along the thread-guiding rod to its normal path.
 10. The device claimed in claim 9, for a frame with a plurality of open end spinning spindles, in which a plurality of thread-guiding elements are provided, and each of the thread-guiding elements being defined by a transverse notch in the thread-guiding rods.
 11. The device as claimed in claim 10, in which the thread guiding rod is mounted for sliding movement in a direction at right angles to the axis of the open end spinnind spindle.
 12. The device as claimed in claim 9 for a frame with a plurality of aligned open end spinning spindles, wherein the direction in which the thread-guiding rod is adapted to slide is parallel to the direction in which the open end spinning spindles are aligned.
 13. The device as claimed in claim 9 further including a motor for rotating the open end spinning spindle, feeding means for feeding the open end spinning spindles with textile fibers, thread withdrawal means, and a tachometer device to actuate the translational sliding movement control means for placing the thread-guiding rod in the longitudinal reserve psoition and insuring stoppage of the feeding means and the withdrawal means, when, after stoppage of the open end spinning spindle driving motor, the decreasing rotary speed of the open end spinning spindle passes through a predetermined threshold spinning speed, and also for restarting the feeding means and the withdrawal means together with the thread-guiding rod pivoting means to temporarily position the thread-guiding element in thread-releasing position when the increasing rotational speed of the open end spinning spindle passes through the pre-determined threshold spinning speed, then to activate the translational sliding movement control means to reset the thread-guiding rod into the operative position. 